I've had this computer for 2 months now. I've had nothing but trouble and now am getting more and more issues with it. If there's a problem with it instead of getting it repaired can I just get a refund and go back to making my own PC?
A refund is unlikely after 2 months. Apple are much more likely to repair or replace. You could sell it after it has been fixed, Macs hold their value well.
Not likely. At most apple will give you a replacement but that's only after a number of significant repairs. Plus there's no hard and fast rule regarding this as well.